1. Field of the Invention
The present invention relates to a magnetic recording/reading device. More particularly, the present invention relates to a pole base loading apparatus and a main chassis for a magnetic recording/reading device.
2. Description of the Related Art
In general, a magnetic recording/reading device such as a video cassette tape recorder, camcorder, and the like, is a device for recording information on a recording medium such as a magnetic tape and reading the information recorded on the recording medium.
Referring to FIG. 1, a magnetic recording/reading device includes a main chassis 10 in which a head drum 11 is rotatably installed, a sub-chassis 20 slidably installed in the main chassis for reciprocation, a pair of reel tables 21 rotatably installed in the sub-chassis 20 for driving the tape reels of a cassette tape, a pair of pole base units 13 and 14 for guiding the tape so that the tape is wound around the head drum 11 when a tape cassette mounted on the sub-chassis 20 is loaded, and a pole base loading device for loading the pole base units 13 and 14.
The respective pole base units 13 and 14 are installed in a pole base guide plate 15 mounted on the main chassis to reciprocate over a predetermined distance. Each of the respective pole base units 13 and 14 is provided with a pole base, a tape guide roller and a fixed pole installed in the pole base.
The pole base loading device includes first and second loading gears 31 and 32 rotatably installed in the pole base guide plate 15, link members 34 and 35 for linking the respective loading gears 31 and 32 to the pole base units 13 and 14, respectively, and a plurality of power transmission gears 36, 37 and 38 for transmitting a driving force of a driving motor 16 to the loading gear 31.
When the power transmission gear 38 receives the driving force of the driving motor 16 and rotates, the first and second loading gears 31 and 32, which interlock with each other, rotate simultaneously. Thus, the link members 34 and 35 rotate, and their knuckles are unfolded to move the pole base units 13 and 14 to the left/right side of the head drum 11.
Referring to FIG. 2, the respective loading gears 31 and 32 are fixed to the guide plate 15 by riveting studs 41 and 42 into the steel plate of the guide plate 15, and forming stepped portions 41a and 42a at the lower ends of the studs 41 and 42, respectively. The stepped portions 41a and 42a pass through stud holes of the loading gears 31 and 32, and are hooked on projections 31a and 32a prepared at the center of a lower part of the loading gears 31 and 32. Accordingly, the loading gears 31 and 32 are fixed to the studs 41 and 42 that serve as shafts, and thus the loading gears can rotate wherein the escape of the loading gears in upper or lower directions is prevented.
According to the conventional pole base loading apparatus as constructed above, the stepped portions 41a and 42a should be formed on both of the studs 41 and 42 that serve as shafts, and the projections 31a and 32a of the gears should be inserted into and coupled to the stepped portions 41a and 42a in order to prevent the escape of the loading gears 31 and 32.
However, the studs 41 and 42 are typically made of metal, and the stepped portions 41a and 42a are formed on the metal studs by a cutting process. Since this cutting process is manually performed, the manufacturing process is further complicated and the manufacturing cost is further increased.
Accordingly, a need exists for a system and method for securing the loading gears which simplifies construction and reduces manufacturing costs.